Tuesday, April 29, 2008

How do the North Carolina Polls Compare to the Composition of Early Voters?

In the last two days, surveys of North Carolinians have shown a 12 point Obama lead (Public Policy Polling), a 10 point Obama lead (American Research Group) and a 5 point Obama lead (Survey USA). So far, we aren't seeing the widely divergent polling results that we had about a week before the Pennsylvania primary. On the other hand, there is a big difference between a 5 point Obama lead and a 12 point lead. After all, the former will be seen by pundits as a Clinton win while a double-digit margin would be enough for Obama to claim victory.

For the surveys leading up to Pennsylvania, I blogged about comparisons between the demographic compositions of the samples drawn by different pollsters. I present some similar comparisons here between the last three polls taken in North Carolina. However, North Carolina's Board of Elections offers us an additional interesting tool in evaluating the composition of these surveys' samples--a tally of actual early voters. As of Tuesday morning, over 144,000 voters had cast early ballots in the Democratic presidential primary. The racial, gender, and party balance of those voters is presented in the table below.

For the most part, the composition of the pollsters' samples appear to be fairly close to that of those who have voted early so far. However, there are some small differences. For example, each polling organization has African Americans comprising one-third of their sample, but so far they have made up 37% of early voters. In addition, 59% of early voters have been women, but the pollsters samples are comprised of slightly fewer women. On the whole, when it comes to race, gender, and party registration, American Research Group appears to have a sample that most closely mirrors the composition of early voters. However, it is important to note that the differences across polling organizations are not major.

One final important point to make is that early voters are not necessarily a representative cross-section of the eventual electorate. Research suggests that those who take advantage of early voting tend to be of higher socioeconomic status than the regular electorate. Only 4.5% of registered Democrats have voted early so far while about 1.8% of those registered as unaffiliated have early voted in the Democratic primary. Bottom line: the early voting figures may be a guide to the eventual composition of the electorate, but right now they represent just a small share of everyone who will eventually vote in this primary.

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